aaron.ballman updated this revision to Diff 100703.
aaron.ballman added a comment.
Addressing review comments.
https://reviews.llvm.org/D33563
Files:
include/clang/AST/Expr.h
lib/AST/ASTDumper.cpp
lib/AST/ASTImporter.cpp
lib/AST/ExprConstant.cpp
lib/CodeGen/CGExprScalar.cpp
lib/CodeGen/CGStmtOpenMP.cpp
lib/Sema/SemaDeclCXX.cpp
lib/Sema/SemaExpr.cpp
lib/Sema/SemaPseudoObject.cpp
lib/Serialization/ASTReaderStmt.cpp
lib/Serialization/ASTWriterStmt.cpp
test/Misc/ast-dump-stmt.c
Index: test/Misc/ast-dump-stmt.c
===================================================================
--- test/Misc/ast-dump-stmt.c
+++ test/Misc/ast-dump-stmt.c
@@ -33,3 +33,35 @@
// CHECK-NEXT: OpaqueValueExpr
// CHECK-NEXT: IntegerLiteral
// CHECK-NEXT: IntegerLiteral
+
+void TestUnaryOperatorExpr(void) {
+ char T1 = 1;
+ int T2 = 1;
+
+ T1++;
+ T2++;
+ // CHECK: UnaryOperator{{.*}}postfix '++' cannot overflow
+ // CHECK-NEXT: DeclRefExpr{{.*}}'T1' 'char'
+ // CHECK-NOT: UnaryOperator{{.*}}postfix '++' cannot overflow
+ // CHECK: DeclRefExpr{{.*}}'T2' 'int'
+
+ -T1;
+ -T2;
+ // CHECK: UnaryOperator{{.*}}prefix '-' cannot overflow
+ // CHECK-NEXT: ImplicitCastExpr
+ // CHECK-NEXT: ImplicitCastExpr
+ // CHECK-NEXT: DeclRefExpr{{.*}}'T1' 'char'
+ // CHECK-NOT: UnaryOperator{{.*}}prefix '-' cannot overflow
+ // CHECK: ImplicitCastExpr
+ // CHECK: DeclRefExpr{{.*}}'T2' 'int'
+
+ ~T1;
+ ~T2;
+ // CHECK: UnaryOperator{{.*}}prefix '~' cannot overflow
+ // CHECK-NEXT: ImplicitCastExpr
+ // CHECK-NEXT: ImplicitCastExpr
+ // CHECK-NEXT: DeclRefExpr{{.*}}'T1' 'char'
+ // CHECK-NOT: UnaryOperator{{.*}}prefix '~' cannot overflow
+ // CHECK: ImplicitCastExpr
+ // CHECK: DeclRefExpr{{.*}}'T2' 'int'
+}
Index: lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- lib/Serialization/ASTWriterStmt.cpp
+++ lib/Serialization/ASTWriterStmt.cpp
@@ -490,6 +490,7 @@
Record.AddStmt(E->getSubExpr());
Record.push_back(E->getOpcode()); // FIXME: stable encoding
Record.AddSourceLocation(E->getOperatorLoc());
+ Record.push_back(E->canOverflow());
Code = serialization::EXPR_UNARY_OPERATOR;
}
Index: lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- lib/Serialization/ASTReaderStmt.cpp
+++ lib/Serialization/ASTReaderStmt.cpp
@@ -536,6 +536,7 @@
E->setSubExpr(Record.readSubExpr());
E->setOpcode((UnaryOperator::Opcode)Record.readInt());
E->setOperatorLoc(ReadSourceLocation());
+ E->setCanOverflow(Record.readInt());
}
void ASTStmtReader::VisitOffsetOfExpr(OffsetOfExpr *E) {
Index: lib/Sema/SemaPseudoObject.cpp
===================================================================
--- lib/Sema/SemaPseudoObject.cpp
+++ lib/Sema/SemaPseudoObject.cpp
@@ -527,9 +527,12 @@
(result.get()->isTypeDependent() || CanCaptureValue(result.get())))
setResultToLastSemantic();
- UnaryOperator *syntactic =
- new (S.Context) UnaryOperator(syntacticOp, opcode, resultType,
- VK_LValue, OK_Ordinary, opcLoc);
+ UnaryOperator *syntactic = new (S.Context) UnaryOperator(
+ syntacticOp, opcode, resultType, VK_LValue, OK_Ordinary, opcLoc,
+ !resultType->isDependentType()
+ ? S.Context.getTypeSize(resultType) >=
+ S.Context.getTypeSize(S.Context.IntTy)
+ : false);
return complete(syntactic);
}
@@ -1639,9 +1642,9 @@
Expr *syntax = E->getSyntacticForm();
if (UnaryOperator *uop = dyn_cast<UnaryOperator>(syntax)) {
Expr *op = stripOpaqueValuesFromPseudoObjectRef(*this, uop->getSubExpr());
- return new (Context) UnaryOperator(op, uop->getOpcode(), uop->getType(),
- uop->getValueKind(), uop->getObjectKind(),
- uop->getOperatorLoc());
+ return new (Context) UnaryOperator(
+ op, uop->getOpcode(), uop->getType(), uop->getValueKind(),
+ uop->getObjectKind(), uop->getOperatorLoc(), uop->canOverflow());
} else if (CompoundAssignOperator *cop
= dyn_cast<CompoundAssignOperator>(syntax)) {
Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, cop->getLHS());
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -11872,6 +11872,16 @@
return CreateBuiltinBinOp(OpLoc, Opc, LHSExpr, RHSExpr);
}
+static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) {
+ if (T.isNull() || T->isDependentType())
+ return false;
+
+ if (!T->isPromotableIntegerType())
+ return true;
+
+ return Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy);
+}
+
ExprResult Sema::CreateBuiltinUnaryOp(SourceLocation OpLoc,
UnaryOperatorKind Opc,
Expr *InputExpr) {
@@ -11879,6 +11889,8 @@
ExprValueKind VK = VK_RValue;
ExprObjectKind OK = OK_Ordinary;
QualType resultType;
+ bool CanOverflow = false;
+
if (getLangOpts().OpenCL) {
QualType Ty = InputExpr->getType();
// The only legal unary operation for atomics is '&'.
@@ -11903,6 +11915,7 @@
Opc == UO_PostInc,
Opc == UO_PreInc ||
Opc == UO_PreDec);
+ CanOverflow = isOverflowingIntegerType(Context, resultType);
break;
case UO_AddrOf:
resultType = CheckAddressOfOperand(Input, OpLoc);
@@ -11916,9 +11929,11 @@
}
case UO_Plus:
case UO_Minus:
+ CanOverflow = isOverflowingIntegerType(Context, Input.get()->getType());
Input = UsualUnaryConversions(Input.get());
if (Input.isInvalid()) return ExprError();
resultType = Input.get()->getType();
+
if (resultType->isDependentType())
break;
if (resultType->isArithmeticType()) // C99 6.5.3.3p1
@@ -11938,10 +11953,12 @@
<< resultType << Input.get()->getSourceRange());
case UO_Not: // bitwise complement
+ CanOverflow = isOverflowingIntegerType(Context, Input.get()->getType());
Input = UsualUnaryConversions(Input.get());
if (Input.isInvalid())
return ExprError();
resultType = Input.get()->getType();
+
if (resultType->isDependentType())
break;
// C99 6.5.3.3p1. We allow complex int and float as a GCC extension.
@@ -12053,7 +12070,7 @@
CheckArrayAccess(Input.get());
return new (Context)
- UnaryOperator(Input.get(), Opc, resultType, VK, OK, OpLoc);
+ UnaryOperator(Input.get(), Opc, resultType, VK, OK, OpLoc, CanOverflow);
}
/// \brief Determine whether the given expression is a qualified member
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -11111,10 +11111,12 @@
BO_NE, S.Context.BoolTy,
VK_RValue, OK_Ordinary, Loc, FPOptions());
- // Create the pre-increment of the iteration variable.
- Expr *Increment
- = new (S.Context) UnaryOperator(IterationVarRef.build(S, Loc), UO_PreInc,
- SizeType, VK_LValue, OK_Ordinary, Loc);
+ // Create the pre-increment of the iteration variable. We can determine
+ // whether the increment will overflow based on the value of the array
+ // bound.
+ Expr *Increment = new (S.Context)
+ UnaryOperator(IterationVarRef.build(S, Loc), UO_PreInc, SizeType,
+ VK_LValue, OK_Ordinary, Loc, Upper.isMaxValue());
// Construct the loop that copies all elements of this array.
return S.ActOnForStmt(
Index: lib/CodeGen/CGStmtOpenMP.cpp
===================================================================
--- lib/CodeGen/CGStmtOpenMP.cpp
+++ lib/CodeGen/CGStmtOpenMP.cpp
@@ -2580,7 +2580,7 @@
OK_Ordinary, S.getLocStart(), FPOptions());
// Increment for loop counter.
UnaryOperator Inc(&IVRefExpr, UO_PreInc, KmpInt32Ty, VK_RValue, OK_Ordinary,
- S.getLocStart());
+ S.getLocStart(), true);
auto BodyGen = [Stmt, CS, &S, &IV](CodeGenFunction &CGF) {
// Iterate through all sections and emit a switch construct:
// switch (IV) {
Index: lib/CodeGen/CGExprScalar.cpp
===================================================================
--- lib/CodeGen/CGExprScalar.cpp
+++ lib/CodeGen/CGExprScalar.cpp
@@ -150,7 +150,7 @@
// If a unary op has a widened operand, the op cannot overflow.
if (const auto *UO = dyn_cast<UnaryOperator>(Op.E))
- return IsWidenedIntegerOp(Ctx, UO->getSubExpr());
+ return !UO->canOverflow();
// We usually don't need overflow checks for binops with widened operands.
// Multiplication with promoted unsigned operands is a special case.
@@ -1763,7 +1763,7 @@
}
case CK_IntToOCLSampler:
- return CGF.CGM.createOpenCLIntToSamplerConversion(E, CGF);
+ return CGF.CGM.createOpenCLIntToSamplerConversion(E, CGF);
} // end of switch
@@ -1819,7 +1819,7 @@
return Builder.CreateNSWAdd(InVal, Amount, Name);
// Fall through.
case LangOptions::SOB_Trapping:
- if (IsWidenedIntegerOp(CGF.getContext(), E->getSubExpr()))
+ if (!E->canOverflow())
return Builder.CreateNSWAdd(InVal, Amount, Name);
return EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(E, InVal, IsInc));
}
@@ -1900,11 +1900,9 @@
} else if (type->isIntegerType()) {
// Note that signed integer inc/dec with width less than int can't
// overflow because of promotion rules; we're just eliding a few steps here.
- bool CanOverflow = value->getType()->getIntegerBitWidth() >=
- CGF.IntTy->getIntegerBitWidth();
- if (CanOverflow && type->isSignedIntegerOrEnumerationType()) {
+ if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) {
value = EmitIncDecConsiderOverflowBehavior(E, value, isInc);
- } else if (CanOverflow && type->isUnsignedIntegerType() &&
+ } else if (E->canOverflow() && type->isUnsignedIntegerType() &&
CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) {
value =
EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(E, value, isInc));
Index: lib/AST/ExprConstant.cpp
===================================================================
--- lib/AST/ExprConstant.cpp
+++ lib/AST/ExprConstant.cpp
@@ -3165,11 +3165,6 @@
return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
}
-static bool isOverflowingIntegerType(ASTContext &Ctx, QualType T) {
- return T->isSignedIntegerType() &&
- Ctx.getIntWidth(T) >= Ctx.getIntWidth(Ctx.IntTy);
-}
-
namespace {
struct CompoundAssignSubobjectHandler {
EvalInfo &Info;
@@ -3291,7 +3286,7 @@
namespace {
struct IncDecSubobjectHandler {
EvalInfo &Info;
- const Expr *E;
+ const UnaryOperator *E;
AccessKinds AccessKind;
APValue *Old;
@@ -3363,8 +3358,7 @@
if (AccessKind == AK_Increment) {
++Value;
- if (!WasNegative && Value.isNegative() &&
- isOverflowingIntegerType(Info.Ctx, SubobjType)) {
+ if (!WasNegative && Value.isNegative() && E->canOverflow()) {
APSInt ActualValue(Value, /*IsUnsigned*/true);
return HandleOverflow(Info, E, ActualValue, SubobjType);
}
@@ -3371,8 +3365,7 @@
} else {
--Value;
- if (WasNegative && !Value.isNegative() &&
- isOverflowingIntegerType(Info.Ctx, SubobjType)) {
+ if (WasNegative && !Value.isNegative() && E->canOverflow()) {
unsigned BitWidth = Value.getBitWidth();
APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
ActualValue.setBit(BitWidth);
@@ -3433,7 +3426,7 @@
AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
- IncDecSubobjectHandler Handler = { Info, E, AK, Old };
+ IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old};
return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
}
@@ -8812,7 +8805,7 @@
return false;
if (!Result.isInt()) return Error(E);
const APSInt &Value = Result.getInt();
- if (Value.isSigned() && Value.isMinSignedValue() &&
+ if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() &&
!HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
E->getType()))
return false;
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -4658,14 +4658,13 @@
if (!SubExpr)
return nullptr;
- return new (Importer.getToContext()) UnaryOperator(SubExpr, E->getOpcode(),
- T, E->getValueKind(),
- E->getObjectKind(),
- Importer.Import(E->getOperatorLoc()));
+ return new (Importer.getToContext()) UnaryOperator(
+ SubExpr, E->getOpcode(), T, E->getValueKind(), E->getObjectKind(),
+ Importer.Import(E->getOperatorLoc()), E->canOverflow());
}
-Expr *ASTNodeImporter::VisitUnaryExprOrTypeTraitExpr(
- UnaryExprOrTypeTraitExpr *E) {
+Expr *
+ASTNodeImporter::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E) {
QualType ResultType = Importer.Import(E->getType());
if (E->isArgumentType()) {
Index: lib/AST/ASTDumper.cpp
===================================================================
--- lib/AST/ASTDumper.cpp
+++ lib/AST/ASTDumper.cpp
@@ -2047,6 +2047,8 @@
VisitExpr(Node);
OS << " " << (Node->isPostfix() ? "postfix" : "prefix")
<< " '" << UnaryOperator::getOpcodeStr(Node->getOpcode()) << "'";
+ if (!Node->canOverflow())
+ OS << " cannot overflow";
}
void ASTDumper::VisitUnaryExprOrTypeTraitExpr(
Index: include/clang/AST/Expr.h
===================================================================
--- include/clang/AST/Expr.h
+++ include/clang/AST/Expr.h
@@ -1717,20 +1717,20 @@
private:
unsigned Opc : 5;
+ unsigned CanOverflow : 1;
SourceLocation Loc;
Stmt *Val;
public:
+ UnaryOperator(Expr *input, Opcode opc, QualType type, ExprValueKind VK,
+ ExprObjectKind OK, SourceLocation l, bool CanOverflow = false)
+ : Expr(UnaryOperatorClass, type, VK, OK,
+ input->isTypeDependent() || type->isDependentType(),
+ input->isValueDependent(),
+ (input->isInstantiationDependent() ||
+ type->isInstantiationDependentType()),
+ input->containsUnexpandedParameterPack()),
+ Opc(opc), CanOverflow(CanOverflow), Loc(l), Val(input) {}
- UnaryOperator(Expr *input, Opcode opc, QualType type,
- ExprValueKind VK, ExprObjectKind OK, SourceLocation l)
- : Expr(UnaryOperatorClass, type, VK, OK,
- input->isTypeDependent() || type->isDependentType(),
- input->isValueDependent(),
- (input->isInstantiationDependent() ||
- type->isInstantiationDependentType()),
- input->containsUnexpandedParameterPack()),
- Opc(opc), Loc(l), Val(input) {}
-
/// \brief Build an empty unary operator.
explicit UnaryOperator(EmptyShell Empty)
: Expr(UnaryOperatorClass, Empty), Opc(UO_AddrOf) { }
@@ -1745,6 +1745,15 @@
SourceLocation getOperatorLoc() const { return Loc; }
void setOperatorLoc(SourceLocation L) { Loc = L; }
+ /// Returns true if the unary operator can cause an overflow. For instance,
+ /// signed int i = INT_MAX; i++;
+ /// signed char c = CHAR_MAX; c++;
+ /// Due to integer promotions, c++ is promoted to an int before the postfix
+ /// increment, and the result is an int that cannot overflow. However, i++
+ /// can overflow.
+ bool canOverflow() const { return CanOverflow; }
+ void setCanOverflow(bool C) { CanOverflow = C; }
+
/// isPostfix - Return true if this is a postfix operation, like x++.
static bool isPostfix(Opcode Op) {
return Op == UO_PostInc || Op == UO_PostDec;
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